Due to its advantages of excellent monochromaticity, high directivity, high luminous flux and the like, at present, the laser light as excellent coherent light has been widely applied in various fields, such as industry, healthcare, science & research, information and military. In the display field, it is more and more common to use the laser light as a light source.
Since the laser light is a high-energy light beam, small light spots are formed generally by beam shaping during the transmission thereof in a light path, so that the energy density of the laser becomes higher. If the energy density of the light spots is not uniform, it is likely to cause burns due to a too large local impact onto an optical lens, and meanwhile, non-uniform image brightness is caused after the light spots enter a lighting system of a light engine and are then projected. Therefore, it is expected that the utilized laser beam is a homogenized light beam. In the applications of the laser light, a light homogenizing component is a very important element, for example, a light stick, a diffuser film, a fly's-eye lens or the like. Wherein, the light stick is common, and is generally located at an output end of a light source and an input end of the lighting system of the light engine. The light stick can reflect light entering the interior of the light stick for multiple times so as to homogenize the light beam. Meanwhile, in accordance with the principle of constant etendue, the divergent angle of light can also be changed by adjusting the area of the incident end and the area of the emergent end of the light stick. However, since the light stick is generally made of glass and thus fragile, the light stick needs to be protected against breaking.